1,1&#39;-dialkyl-3,3&#39;-alkylenebenzimidazolocyanine salts



Patented Aug. 16, 1949 UNI-TED: STATES P2 i-TENT" OFFICE Ll'i-DIALKYL-3;3-AEKYLENEBENZM= DAZOLOCYANIN'ESALTS'J: Leslie G.1S.'=Brook'er, Rochester;sNJYKassignor to.

Eastman Kodak :fiompany Rochester," N: Y2, ,a corporation of New J ersey No wDrawing.v Application August 17, 1945, Serial No. 611,240

6 'Clairns': (Cl. 260240) This. inventions. relates-1 to 1,-1'- dialkyl-. ,3 4- alkylene-benzimidazolocyanine salts and to a process for preparing the same.

It is shown in the copendingr application of Leslie G. S. Brooker and Robert'l-ls Sprague, Serial No; 563,086, filed-November 11, 1944 (of which the instant. application is a,continuationin-part) that N;N-alkylenecyanine'p-toluenesulfonates, e. g. N,N-alkylenethiacyanine p-toluenesulfonates, can beprepared by reacting with an alkylen'e salt of the following'general formula:

whereinwrepresents a positive-integer offrom 2 to-3,:and X and X" eachrepresents anaryl'sulfo' nate radical; upon a heterocyclicbasederivative of methane of theiollowing general formula:

wherein Z and Z each represents the non-metal li'c atoms necessary to complete 'aheterocyclic nucleus: containing-5 to --6-"atoms in theh'eterocyclic ring, followed by reacting upon the-result ing hydro salt with an acid-binding agent;

It isan object of the present invention to pro vide' 1,1 -dialkyl -3,3 -alkylenebenzimidazolocyanine salts in which the alkylene group. contains from 2 to 3 carbon atoms and. also to proe vide 1,1-dialkyl-3,3'-methylenebenzimidazolocyanine salts by means of a difierent process. Other objects will become apparent hereinafter. In accordance with .myinvention I provide the 1,1 -dia1kyl-3,3 -alkylenebenzimidazolocyanine salts (dyes) which ares-represented by the following general formula; 1., R1, l tl. i D" (ELI-401110? 15:-v H

\(CH2)"%" V wherein D represents an o-phenylene group substituted or unsubstituted, n represents a positive integer of from 1 to 3, R represents an alkyl group, and X represents an anion:

The salts; wherein nrepresentsa positive integer of from: 2 to 3,1 are prepared, in ,accordance with my invention; by reactingwith' an alkylene salt of the followinggeneralformula:

wherein X andXCeach represents an aryl sulfol w nate radical, and n representslapositiveinteaen of from 2 to 3, upon a heterocyclic base derivative of methane ofthe following eneral formula:

D Slf-CHPCY wherein:D' representsran; oz-phenyiene' groupaand R represents' analk'yl: group, -fol'lowedsiby-2reacting upon the resulting 'hydro 'salt with-am acid 'binding agent. process can be illustrated schematically for-the preparatibn of 1,1" -diethyl-i 3;3'-=ethylenebenzimidazolocyanine-= p toluene-z sulfbnate as foll'owsz (Hydra-salt) 3 ;"Acid-bindln'g agent e; g. l- (ores): j

"T-e (051mm so; one-04' o in:

(50H; an?

5a The N,N'--alky;1ene .arylsulfonates so formed are advantageouslyconverted to theamore insoluble cyanine iodidesto facilitate isolation from the reaction mixture, .bytreatment with sodium or potassium iodide. Th'ezcyanine bromides and 5 perehloratespanbesimilarly obtained sodium carbonate, ammonia or other -acid-bind- As alkylene arylsulfonates, "alkylen'eing agent. p-toluenesulfon-ates are advantageously employ-ed, although alkylene benzene sulfonates and other alkylene aryl sulfonates can be employed.

The following examples will serve to illustrate,

further my new salts and the manner of obtaining the same.

Example 1.1,1 -diethyl-3,3 -ethylenebenzimidaeolocyanine iodide $1 I q q (I c-... O N N CH Og I 3 g. (1 mol.) of di-l-ethylbenzimidazolylmethane was mixed with ethylene-p-toluenesulfonate (3.8 g., 1 mol.) and the mixture was heated at 110 C. (oil bath). Vigorous reaction occurred, after which heating was continued at 165 C. for 1 hour. The cooled reaction mixture was dissolved in ethyl alcohol and to the solution was added sodium hydroxide. The ethylenecyanine dye separated from the solution. The dye was filtered 01f, washed with water and dissolved in hot ethyl alcohol. To the hot solution was added 1.5 g. of sodium iodide dissolved in ethyl alcohol. The ethylene cyanine iodide which separated from the cooled mixture was filtered 01f and purified by recrystallization from ethyl alcohol. It was obtained as tan crystalshaving a melting point about 325 C. Its ethyl alcohol solution had a strong blue fluorescence.

Using trimethylene di-p-toluenesulfonate, 1,1.- diethyl-3,3-trimethylenebenzimidazolocyanineiodide can be prepared in a similar manner. Using di-l-methylbenzimidazolylmethane, 1,1'-dimethyl-3,3'-ethy1enebenzimidazolocyanine iodide can be prepared in a similar manner.

In accordance with my invention, I prepare 3,3-methylenebenzimidazolocyanine salts by reacting a methylene halide upon a heterocyclic base derivative of methane of the above general Formula III, followed by reacting upon the resulting hydrohalide with an acid-binding agent. Methylene bromide or methylene iodide are advantageously employed and any of the aforesaid acid-binding agents can be used.

The following example will serve to illustrate the methylenebenzoimidazolocyanine salts and the manner of obtaining the same.

Example 2. 1,1'-diethyZ-3,3'-methylenebenzi midaeolocyanzne iodide C2115 2115 CH2 3 g. (1 mol.) of di-l-ethylbenzimidazolylnine iodide can be prepared.

methane were mixed with methylene iodide (1.2 00., 1 mol. 100% excess) in a large diameter test tube and heated over a free flame with stirring. The reaction proceeded smoothly. The cooled reaction mass was dissolved in methyl alcohol and aqueous caustic soda solution was added until the solution was alkaline. The methylene benzimidazolocyanine iodide separated out (0.75 g. It was filtered off, washed with water and recrystallized from ethyl alcohol. It was obtained as pale yellow crystals melting above 320 C. Its ethyl alcohol solution was nearly colorless with a strong blue fluorescence.

Using di 1 methylbenzimidazolylmethane, 1,1'-dimethyl 3,3 methylenebenzimidazolocya The di-1-ethylbenzimidazolylmethane used in the foregoing examples can be prepared as illustrated in the following example.

Example 3.-Di-1-ethylbenzimidazolylmethane C 2H5 C 2H5 13.6 g.(2 mol.) of N-ethyl-o-phenylenediamine (Hempel, J. prakt. Chem. 41, 164 (1890); 39, 199 (1889)) were mixed with 8 g. (1 mol.) of ethyl malonate and the mixture heated gently under reflux for 2 hours. The cooled solid reaction mixture was purified by recrystallization from ligroin (B. P. -120 C.). The compound had th above formula and melted at 107 :to 117 C. with shrinking from 103 C.

Similarly di-1-methylbenzimidazolylmethane can be prepared using N-methyl-o-phenylenediamine.

The herein-described salts can be employed in the manufacture of optical filters useful in photography.

What I claim as my invention and desire to be secured by Letters Patent of the Unitde States is:

1. The alkylene benzimidazolocyanine salts which are represented by the following general formula:

R R l l.

wno.

cnon \I wherein R represents an alkyl group containing from 1 to 2 carbon atoms and n represents a positive integer of from 1 to 3.

4. The alkylene benzimldazolocyanine salt of the following formula:

CzHs

CH2 I 5. The alkylene benzimidazolocyanine salts of the following general formula:

wherein R represents an alkyl group containing from 1 to 2 carbon atoms.

6 6. The alkylene benzimidazolocyanlne salts which are represented by the following general formula:

wherein D represents an o-phenylene group, R represents an alkyl group containing from 1 to 2 carbon atoms, X represents an anion and n represents a positive integer of from 1 to 3.

LESLIE G. S. BROOKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,265,907 Kendal Dec. 9, 1941 2,320,654 Reister June 1, 1943 2,393,351 Wilson Jan. 22, 1946 OTHER REFERENCES Schelber Berichte 59, pages 502-508. 

